Jumping reflex-reflection

ABSTRACT

The jumping reflex-reflectors disclosed are eye-catching attention-getting safety devices. They have at least one primary rotatable part, an axis means establishing a predetermined axis for rotation of the primary rotatable part, and holding means for the axis means to permit the rotation, especially a wind-actuated rotation. The primary rotatable part comprises a form-retaining body, preferably a base sheet material. This base sheet is aligned with substantially all portions of it extending substantially parallel with the predetermined axis for its rotation. It is contoured at least in portions outwardly from the axis; and patterned areas of reflex-reflecting material and of non-reflex-reflecting material (preferably fluorescent) are disposed on opposite sides of it. The patterned area of reflexreflecting material on one side is relatively displaced in axial relationship from the patterned area of reflex-reflecting material on the other side. In all cases, at least 50 percent of the area coverage of each reflex-reflecting pattern on opposite sides of the sheet material is in locations relative to the axis which do not coincide as viewed during rotation of the rotatable part. The patterned areas of non-reflex-reflecting material on opposite sides of the sheet material also are relatively displaced in axial relationship to each other. The arrangement is such that, at substantially all practical rotation speeds for the primary rotatable part about the predetermined axis, a viewer under reflex-reflecting conditions gains the impression of shifting flash patterns of light return suggestive of the patterns of the areas of reflex-reflecting material. A variety of rotatable bodies and reflex-reflecting pattern arrangements are disclosed.

United States Patent 11 1 Douglas [451 Sept. 11, 1973 1 1 JUMPINGREFLEX-REFLECTION [75] Inventor: Donald J. Douglas, White Bear Lake,

Minn.

[73] Assignee: Nu-Pro, Inc., St. Paul, Minn.

[22] Filed: May 8, 1972 [21] Appl. No.: 251,431

[52] US. Cl 350/97, 40/39, 350/99 51 1111.01. G02b 5/12 [58] Field ofSearch 350/97, 99, I03, 350/288; 40/39, 126 B; 116/63 [56] ReferencesCited UNITED STATES PATENTS 2,314,508 3/1943 Monteleone 40/39 2,781,0172/1957 Fuller et al. 350/99 2,693,044 1 H1954 Roemisch 40/39 588,0608/1397 Fruit 40/39 3,073,047 l/l963 Jones 40/39 2,810,223 10/1957Fraesdorf 40/39 2,701,928 2/1955 Keenan et al.... 40/39 3,292,56912/1966 Trigilio 350/99 Primary ExaminerDavid Schonberg AssistantExaminerMichael J. Tokar Att0rneyRobert C. Baker [57] ABSTRACT Thejumping reflex-reflectors disclosed are eyecatching attention-gettingsafety devices. They have at least one primary rotatable part, an axismeans establishing a predetermined axis for rotation of the primaryrotatable part, and holding means for the axis means to permit therotation, especially a wind-actuated rotation. The primary rotatablepart comprises a formretaining body, preferably a base sheet material.This base sheet is aligned with substantially all portions of itextending substantially parallel with the predetermined axis for itsrotation. It is contoured at least in portions outwardly from the axis;and patterned areas of reflexrefiecting material and ofnon-reflex-reflecting material (preferably fluorescent) are disposed onopposite sides of it. The patterned area of reflex-reflecting materialon one side is relatively displaced in axial relationship from thepatterned area of reflex-reflecting material on the other side. In allcases, at least 50 percent of the area coverage of eachreflex-reflecting pattern on opposite sides of the sheet material is inlocations relative to the axis which do not coincide as viewed duringrotation of the rotatable part. The patterned areas ofnonreflex-reflecting material on opposite sides of the sheet materialalso are relatively displaced in axial relationship to each other. Thearrangement is such that, at substantially all practical rotation speedsfor the primary rotatable part about the predetermined axis, a viewerunder reflex-reflecting conditions gains the impression of shiftingflash patterns of light return suggestive of the patterns of the areasof reflex-reflecting material. A variety of rotatable bodies andreflexreflecting pattern arrangements are disclosed.

22 Claims, 9 Drawing Figures JUMPING REFLEX-REFLECTION This inventionrelates to safety warning devices, and more particularly to eye-catchingattention-getting safety devices having patterned areas ofreflexreflecting material thereon.

All safety warning devices of this invention are adapted to exhibit afunctional performance which provides a viewer under reflex-reflectingconditions with the impression of leaping or shifting or jumping flashpatterns of light return; and the devices hereof exhibit such functionalperformance entirely throughout a circle of 360 around them.

A daytime safety warning feature for reflex-reflecting devices hereof iscreated by additionally employing special patterned areas of fluorescentmaterial in such a way as to cause leaping or jumping patterns offluorescent light.

In primary structural embodiments of this invention, a form-retainingcontoured base sheet material is so aligned with respect to apredetermined axis that substantially all portions of the sheet materialextend sub stantially parallel with that axis. Rotation of the sheetmaterial takes place about that axis; and wind actuation of the rotationis normally relied upon. Patterned areas of reflex-reflecting materialand of non-reflexreflecting-material (e.g., fluorescent) on the basesheet material provide a viewer under reflex-reflecting conditions withthe leaping or shifting or jumping flash patterns more fully discussedhereinafter.

Reflex-reflective teachings herein may be incorporated in a variety ofstructural and functional relationships, especially in combination withfluorescent patterns, to provide devices useful as safety warningdevices for moving vehicles, especially slow moving vehicles such asbicycles, farm vehicles, and the like. Devices hereof may also be usedat stationary locations, such as on a road bed or shoulder near astalled vehicle, or at various elevated locations, such as on a post orsign frame or support. When mounted or placed at a stationary location,with air currents or wind relied upon to effect rotational movement, itis desirable to choose a location which is apt to receive gusts of windor a churning or turbulence of air (as commonly caused by a passingvehicle) sufficient to effect the desired rotational movement; butpowered means to effect the rotational movement, although not desiredand certainly not necessary in practicing the preferred teachingshereof, may optionally be employed. A major purpose of the invention isthat of providing eye-catching attention-getting safety devices relyingupon wind or air movement for the rotational effects.

One problem in gaining wide-spread usage of safety warning devices bybicycle riding youngsters is that of creating a strong desire on thepart of the youngsters to possess the device and to display it properly.The present inventionprovides youngsters with an exciting motion device,activated by the movement of the bicycle down a road. Combined with theexcitement of the motion aspect is the functional feature ofintermittent reflex-reflection ofjumping or shifting character. A nighttime driver of an automobile approaching a bicycle equipped with themotion device of the present invention sees jumping flashes ofreflex-reflected light which attract his eye and command his attention.For daytime safety, fluorescent patterns preferably also are present.Thus, bicycle riding youngsters get excitement and satisfaction from themotion aspect, while the driving public gains the benefit of anattention-getting alert for the protection of the youngsters.

Of course, a wide variety of spinning or rotatable devices are known,some including rotating reflexreflectors; and the following U. S.patents are illustrative: Oliver No. 214,694; Warner No. 1,225,379;Dodson No. 1,258,541; Canby No. 1,275,384; Addition No. 1,798,052; ValkNo. 1,906,668; Leamard No. 2,679,711; Fuller et al. No. 2,781,017;Gladen No. 2,797,621; Sly No. 2,890,536; Barker No. 2,943,416; Levey No.2,948,257; Simmons No. 2,965,991; Trigilio No. 3,292,569; Lusebrink No.3,320,920; and Beaubien No. 3,391,487.

However, the reflex-reflecting pattern arrangements as taught herein,particularly the relatively displaced arrangements as explained morefully hereinafter, and the special benefits and functional resultsflowing therefrom, are not, insofar as is known, recognized or suggestedin the prior art (not even in prior art dealing with rotaryreflex-reflectors, such as Fuller et al. US. Pat. No. 2,781,017, andTrigilio US. Pat. No. 3,292,569).

An especially important feature of this invention is that of theflexibility or variety of possible arrangements for the patterns of thereflex-reflecting material on the primary rotatable part of the devicesherein. This is achieved suitably by employing bead-typereflex-reflecting material which is capable of assuming essentially anycurvature or contour as desired. Alternatively, cube-corner typereflex-reflectors may be employed; but such reflectors are not as easilyhandled in creating varied design arrangements, as preferred.

Reflex-reflectors are, of course, well known; and illustrative bead-typeteachings, here incorporated by reference, are contained in thefollowing U. S. Pat. Nos.: Gebhard et al. 2,326,634; Palmquist2,407,680; Palmquist 2,963,378; McKenzie 3,025,764; Palmquist 3,043,196;Nellessen 3,099,637; Nellessen 3,251,704; and Vanstrum 3,274,888.Teachings from these patents as well as still other suitablereflex-reflecting sheet materials and coatings are useful in thepractice of the invention.

Basically reflex-reflectors cause an incident beam of light impingingthereupon to be retro-directed back toward the direction of the lightsource itself, more or less in a brilliant cone having the incident beamas its axis. The light so returned is considered to be retro-reflectedor reflex-reflected; and this is to be distinguished from light returnedfrom a specular flat surface such as a mirror or polished metal surface.Angular light reflected by a specular surface is returned at an angleopposite to normal but approximately equal to the angle at which itimpinged upon the specular surface. In reflex-reflection, the lightreturned from the surface is in a cone with the incident beam as itsaxis even when the incident beam strikes the reflex-reflecting surfaceat angles rather substantially away from a true normal angle (that is,It is this feature, plus the improved quantum of light return toward asource over that exhibited by a specular surface (when both arerevolving), that makes the reflex-reflecting patterns and relationshipstaught herein of critical character in practicing the invention.

characteristically, bead-type reflex-reflectors comprise a layer ofsmall transparent glass beads or sphere lenses or microspheres, plus anunderlying opaque reflecting material, preferably of a specular typesuch as metal flakes or coatings (see, for example, the teachings of theaforenoted patents directed to bead-type reflexreflectors). Lightentering a bead or sphere-lense of the bead layer is refracted, strikesthe underlying reflective material, and then is again refracted on itsreturn trip through the bead. The result is that the light is returnedback toward its source in a brilliant diverging cone.

Eye-catching attention-getting safety devices of the present inventioncomprise at least one primary rotatable part actuatable into rotation,preferably by wind acting thereupon. An axis means is also provided andestablishes a predetermined axis about which rotation of the primaryrotatable part takes place. Holding means for the axis means permitsrotation of the rotatable part.

In the primary embodiments of the invention, the primary rotatable partcomprises a form-retaining base sheet material which is so aligned thatits major portion or substantially all portions of it extendsubstantially parallel with the predetermined axis of rotation. Thissheet material is preferably contoured, usually in a continuous sweepingmanner as it extends outwardly from an axis of rotation for it. Itshould at least be contoured in portions outwardly from thepredetermined axis, so

as to facilitate wind actuation of its rotation. Patterned areas ofreflex-reflecting material and of non-reflexreflecting material are onopposite sides of the base sheet material. The patterned area ofreflex-reflection on one side of the sheet material is relativelydisplaced in axial relationship from the patterned area ofreflexreflecting material on the other side thereof. In essence, atleast 50 percent of the areas of the reflexreflecting patterns onopposite sides of the sheet material are in locations relative to theaxis means which do not coincide as viewed during rotation of theprimary rotatable part. The patterned areas of non-reflexreflectingmaterial on opposite sides of the sheet material also are relativelydisplaced in axial relationship to each other. Thus, rotation of theprimary rotatable part, that is, the base sheet material, about itspredetermined axis provides a viewer under reflex-reflecting conditionswith the impression of shifting flash patterns of light return; andthese flash patterns are suggestive of the patterns of the areas ofreflex-reflecting material on opposite sides of the base sheet.Especially signiflcant is the fact that the single primary rotatablepart performs such as to provide the shifting flash pattern effect,which is quite distinct from the teachings in the prior art, and thefact that the displaced pattern arrangement as taught herein is suchthat the shifting light return therefrom is capable of resolution by thehuman eye under practical use conditions.

Preferably, the reflex-reflecting pattern on one side of the rotatablebase sheet material is substantially identical in overall shape to thereflex-reflecting pattern on the other side thereof; but the patterns onopposite sides are relatively displaced with respect to each other.Further, the predetermined axis of rotation for the base sheet materialgenerally but not always will extend along a line substantiallycoinciding with a line in the plane of the base sheet material.Displaced reflex-reflecting patterns on opposite sides will preferablyextend across the area of the sheet material at the predetermined axisof rotation, which contributes significantly to the gaining of lightreturn of shifting character resolvable as shifting flashes by the humaneye.

In several alternate embodiments of the invention, the primary rotatablepart comprises a form-retaining body having surface viewable areascompletely surrounding and spaced outwardly from the predetermined axisof rotation for the body. At least two patterned areas ofreflex-reflecting material on background areas of non-reflex-reflectingmaterial are on the body, with the patterns relatively displaced fromeach other in both axial relationship and radial relationship on thesurface viewable areas. At least one of the patterns ofreflex-reflecting material does not extend in a circumferentialdirection on the surface viewable areas any more than 180 about thepredetermined axis. Preferred structural bodies comprise at least threediscrete surface viewable areas connected in angular relationship toeach other, with no pattern of reflexreflecting material extending morethan about in a circumferential direction.

The invention and various functional benefits and advantages flowingfrom it will further be described with the aid of a drawing, made a parthereof, wherein:

FIG. I is a plan view ofa safety warning device of the inventionespecially adapted for affixing to the handlebar or a frame part of abicycle;

FIG. 2 is a cross section taken on lines 22 of FIG.

FIGS. 3, 4, 5, 6, and 7 are schematic perspective views of alternateembodiments of the invention;

FIG. 8 is a schematic cross-sectional view of a rotatable partcomprising a body having three discrete surface viewable areas connectedin angular relationship to each other and completely surrounding andspaced outwardly from a predetermined axis for the rotation thereof; and

FIG. 9 is a schematic cross-sectional view of a rotatable sheet materialpart for a safety device according to the invention, with the axis ofrotation displaced from a line extending through the plane of therotatable sheet material part.

The safety device illustrated in FIGS. 1 and 2 will first be described.That device comprises a rotatable part 10 which is a form-retaining basesheet material. Formretaining, as used herein, means a rigid orsemi-rigid or even somewhat flexible type material, but one which, afterpossible deformation under pressure, returns to its original shape orcontour. Generally such sheets are relatively stiff. This part 10 isactuatable into rotation by wind acting thereupon. An axis means 11,suitably formed by stub shaft elements 12 and 13, is provided andestablishes a predetermined axis about which rotation of the primaryrotatable part takes place. Stub pivot elements 12 and 13 extendedoutwardly from perimeter portions of the rotatable sheet material part10. Rotatable sheet part 10 is essentially circular or disk-like inoverall perimeter shape; and the axis pins 12 and 13 suitably may bemolded or formed at the same time part 10 is formed. lllustratively,these parts may be formed out of organic plastic materials such aspolystyrene, polyethylene, polyvinyl chloride (or any of a variety oforganic plastic materials) as well as, if desired, aluminum, or any of avariety of metallic or metal materials.

A closed loop frame 14 of ring-like character, suitably with areinforcing ridge 15, serves as a stationary protective frame forrotatable part 10 and for holding the axis pins 12 and 13 for it.Bearing surfaces or socket recesses 16 and 17 are suitably molded as anintegral part of frame 14 for receiving the pivot stubs or shafts 12 and13 in a manner permitting their rotation.

A bracket 18 may be riveted or otherwise fixed to frame 14, especiallyat a reinforced portion 19 thereof; and the bracket 18 suitably is oneadapted to be fixed to a round bar such as a bicycle handlebar or thelike. A cooperating closure part 20 for the bracket 18 suitably isprovided for attachment as by bolts 21 to the bracket 18. Observe thatthe means 18 for mounting the frame 14 (and therefore the safety deviceper se) to a base object such as a bicycle handlebar is preferably fixedto frame 14 at a location not in alignment with the axis means 11 nor alocation perpendicular thereto. The significance of this is that therotatable part 10 rotates on an axis angularly disposed with respect tothe location of mounting means 18, the angle being between 0 and 90; andthis in turn contributes to the desired disposition of light reflectingpatterns received from the device as it is mounted on a bicyclehandlebar.

The patterns of reflex-reflecting material on the device will nowbediscussed. These are located on the primary rotatable part 10, whichillustratively consists essentially of a form-retaining base sheetmaterial, as aforenoted. This base sheet material is aligned withsubstantially all portions of it extending substantially parallel withthe predetermined axis of rotation for it. However, the base sheetmaterial may be and preferably is contoured as it extends outwardly fromthe axis of rotation, with the contour creating oppositely outturnedleading and trailing edges removed from the axis of rotation. It iscurvi-planar. The contour facilitates wind or air pick-up by therotatable part, and therefore contributes to the wind actuated rotationof it. In short, the oppositely outturned edges are adapted todifferentially intercept air flowing by them, which in turn causesrotation of part 10.

On one face side of the sheet material 10 is located a patterned area 22of reflex-reflecting material. Illustratively, the reflex-reflectingmaterial employed may consist of a flexible prefabricated sheet 22adhesively fixed on base sheet part 10. As shown in FIG. 1, the area 22of reflex-reflecting material covers all portions of the area of thebase sheet material 10 from one stub pivot 12 up to about one-fourth theaxial distance across part 10 from stub 12 to stub 13. The remainingthree-fourths of the face side of the base sheet material 10, as viewedin FIG. 1, is illustratively entirely free of reflex-reflectingmaterial, and is non-reflex-reflecting.

Conversely, the reverse side of the base sheet material 10, as viewed inFIG. 1, is equipped with a pattern of reflex-reflecting material 23extending up to about one-fourth of the axial distance across part 10from the pivot stub 13 toward stub 12. Apart from the two notedreflex-reflecting portions 22 and 23 on opposite sides of the base sheetmaterial 10, the surfaces of part 10 are non-reflex-reflecting. Thoseremaining surface portions suitably may be coated with fluorescentmaterial or afluorescent paint (to provide daytime brillance), butpreferably arenot coated or formed with a specular or mirror-typereflecting material. If the rotatable disk 10 is formed out of metalexhibiting a specular reflecting character, all portions not covered bythe pattern of reflex-reflecting material preferably are painted orcovered with fluorescent paint or layer, or a nonfluorescent but diffusereflecting paint or layer, so as to remove the specular reflectingcharacter from the rotatable disk or base sheet material 10. The reasonfor this is to remove interference for the refelx-reflecting pattern aswould be caused (under some but not all conditions of reflex-reflectiveviewing) by a specular or mirror reflecting surface adjacent areflex-reflecting pattern area on the rotatable part 10.

Reference to viewing under reflex-reflecting conditions, as used herein,refers to viewing a safety device hereof at a location generallyradially outward from (and not in line with) the axis of rotation forthe primary rotatable part of the safety device, and with the eyes ofthe viewer near a source of incident light striking the safety device(such as, for example, is the characteristic viewing circumstance forthe driver of an automobile with the auto headlights operating).

An important feature of the patterned areas of reflexreflection in thedevice illustrated in FIGS. 1 and 2 is that the area ofreflex-reflection identified at numeral 22 becomes viewable only onceduring each complete revolution of the rotatable part 10. Likewise, thearea of reflex-reflection identified by numeral 23 becomes viewable onlyonce on each complete revolution of r0- tatable part 10.

An especially important characteristic of the reflexreflecting patternarrangements taught herein, is that at least 50 percent of the areacoverage of each reflexreflecting pattern on opposite sides of the sheetmaterial is in locations relative to the axis which do not coincide asviewed during rotation of the rotatable part. In other words, a faceview of one side, followed by a face view of the other side, will revealto the viewer that at least 50 percent of the reflex-reflecting areacoverage on one side lies in areas not reflex-reflecting when the basesheet material is reversed for viewing its opposite or other side. As apractical matter, preferred pattern arrangements of the invention aresuch that percent of the pattern on one side does not coincide with theother when the base sheet material is reversed. But in all cases, evenwhen slight overlapping of pattern impressions occurs on rotation, thereflex-reflecting areas on opposite sides are relatively displaced inaxial relationship, that is, in their relative orientation to the axis.In fact, they are preferably very substantially spaced from each otheron opposite sides of rotatable sheet 10 in a direction parallel with theaxis--not only with no axial overlapping or coinciding of the pattern onone side with the pattern on the other, but with a substantialnomreflex-reflecting space between.

The substantial spacing in an axial direction (or direction parallel tothe axis), plus the fact that the areas of reflex-reflection extendacross the axis of rotation as viewed under reflex-reflecting condition,together with the requirement of a complete revolution before eitherarea of reflex-reflection repeats or unfolds itself, and even, to someextent, the substantially continuous contour of the rotatable sheet 10from the axis 11, all contribute to the desired feature of providing aviewer, under reflex-reflecting conditions, with the impression ofjumping flash patterns of light return which are resolvable undersubstantially all practical conditions as flash patterns or flickers bythe human eye.

This resolvability feature is of utmost importance, and is to bedistinguished from the great tendency toward blurring response ascommonly characteristic for heretofore known devices havingreflex-reflectors of identical character not relatively displaced in anaxial relationship on opposite sides of a single revolving vane. Suchheretofore known devices, where the sheet or vane actuatable intorotation by wind is provided with reflex-reflectors, have invariablyspaced the reflex-reflecting areas radially outward from the axis ofrotation, with the area of reflex-reflection on one side coinciding withthe area on the other under viewing conditions. Such areas ofreflex-reflection move by rotation through a sweeping are into view fora viewer, with both areas presenting themselves to a viewer during asingle complete rotation, whereas the patterned reflex-reflecting areasillustrated in FIG. I, (which are axially displaced and extend acrossthe axis of rotation) tend to give the result of unfolding," with eachpresenting itself only once and only momentarily during each completerevolution, which effectively causes the result of a momentary maximumretro-direction of incident light at a particular area on the devicejust once during each revolution. The are sweeping aspect inherent forany portion of a reflex-reflecting area extending radially outward fromthe axis of rotation is substantially overcome or minimized by virtue ofthe unfolding" characteristic of reflex-reflecting patterns which extendover the axis of rotation, as illustrated in FIG. 1. Such is to bedistinguished from a blurring swashbuckling or streaking effectcharacteristic of arc sweeping reflecting areas spaced from the axis ofrotation and not extending over the axis.

Of especial pertinence is that the effect of shifting flashes, asdistinguished from the impression of a single blur, is preserved for theviewer of devices equipped with the pattern arangements as taughtherein, even when the rotatable part spins at a rate in excess of about1,000 revolutions per minute, which in efiect demonstrates that thebenefit of shifting flash performance persists under all practicalenvironmental wind conditions, at least up to about hurricane velocity(and hurricane velocities are not looked upon as practical),

Also, if desired, devices hereof may be equipped with means to cause abraking effect as rotation approaches hurricane velocity; andillustratively, selective high velocity braking may be accomplished byadding a small propeller unit to the axis of rotation. The propellerunit will be substantially ineffective to axially shift the axis meansat low velocity of rotation, but will shift the axis means at raisedvelocities and frictionally press the axis into a bearing for itsrotation, thereby retarding rotation. But this is not really necessary.

As a general rule, the pattern of reflex-reflection on one side of thebase sheet 10 should be, or preferably is, substantially identical inoverall shape to that on the other side of the sheet 10. But, thepattern frequently is preferably inverted on one side with respect tothe other. Thus, the pattern 22 is substantially the mirror image of thepattern 23 on the reverse side, or vice versa. While circular patternsmay be employed, noncircular patterns (or patterns whose perimeter isnoncircular) of reflex-reflection are vastly preferred from thestandpoint of creating recognizably distinct flash return of light onrotation of the device under reflexreflecting conditions. Circularpatterns, even when portions of the interior are broken away or removedto create an image which appears recognizably different on forming amirror inversion of it, are nevertheless not preferred simply becausethe human eye, on very rapidv reflex-reflecting character within thecircle. Under all circumstances, a full disk of reflex-reflection is notpreferred as a pattern. Geometric patterns of some other perimetershape, such as triangle, rectangle, oval, half moon, a strip, or thelike (but preferably not optional alphabet letter or numbers), are muchmore attentiongetting and do not appear as a light bulb. Even arelatively large ring can give useful preferred type results. But soliddisk-like reflex-reflectors generally are not preferred. However,cube-corner reflex-reflectors of varied pattern shapes can be useful,especially where flexible cube-corner sheet materials are employed inmaking the patterns.

Bead-type reflex-reflecting sheet materials or coatings permitconvenient formation of a variety of shapes or patterns for thereflex-reflecting areas in an economical manner. No problem exists inreflex-reflectorizing curved or peculiarly shaped surface areas whenbeadtype reflex-reflectors are employed. For example, reflex-reflectingstructures of any contour may be formed by applying paint compositionswhich upon drying exhibit a reflex-reflection (as, for example, taughtin U. S. Pat. No. 3,251,704). Preferably, however, the patterns areformed by adhesively affixing or otherwise flxing to the rotatable part10 a pattern cut from previously fabricated thin bead-typereflex-reflecting sheet material, and an especially desired sheet toemploy is one having a transparent cover film over a base exposed lensestructure such as shown in Gebhard et al. US. Pat. No. 2,236,634, with ahoneycomb pattern of line seals securing the transparent cover film tothe base structure and forming a plurality of cell spaces ofreflex-reflecting character.

The most preferred pattern arrangements for shifting reflex-reflectionare axially separated on opposite sides by an axial spacing distance ofat least about one-third the axial distance of the rotatable sheetmaterial (the distance of separation being preferably greater asanticipated rate of rotation increases), with all other areas coveredwith fluorescent material for daytime attention-getting properties.Optionally, the fluorescent pattern areas may be separated by an axialspacing distance equal to or lesser or greater than that for the areasof reflex-reflection.

In the safety device illustrated in FIG. 3, an open loop frame orU-shaped frame 26 is employed for holding the essentially square orrectangular contoured base sheet material 27 for rotation about apredetermined axis formed by pivot stubs 28 and 29. A base plate 30 maybe employed as a foundation piece for holding frame 26 in an uprightposition. Form-retaining base sheet material 27 is provided with a stripof reflexreflecting material 31 on one side, with the edge 33 of thatstrip extending perpendicular to the axis of rotation at a pointpreferably no more'than about one-third of the distance from the topedge of the base sheet to the bottom edge thereof. Another patternedstrip of reflex-reflecting material 32, on the opposite side of basesheet 27, extends with its edge 34 about one-third the distance from thebottom of the base sheet 27. Shifting reflex-reflective performance forthe structure in FIG. 3 is substantially similar to that for thestructure illustrated in FIG. I.

The device illustrated in FIG. 4 is a device capable of performinganalogously to moving lights of a display sign; but no source of poweris needed. In FIG. 4, a single axis means 35, such as a shaft or rod, ismounted for rotation in a base plate or holding means 36. Only one endof the axis shaft 35 is illustrated as being so mounted. Spaced alongthe axis shaft 35, and rotatable about the axis means provided by rod35, are a plurality of rotatable parts, including a base or primaryrotatable part 37, plus a secondary part 38, with optionally a stillfurther secondary rotatable part 39. The rotatable parts are all axiallydisplaced from each other; and each rotatable part, in the showing ofFIG. 4, consists essentially of a form-retaining curvi-planar sheetmaterial aligned with substantially all portions thereof extendingsubstantially parallel with the predetermined axis of rotationestablished by axis means 35. Further, the sheet material of primaryrotatable part 37 is radially displaced in orientation (as at a 90angle) from the sheet material of rotatable part 38. Indeed, the sheetmaterial of rotatable part 39 may be radially displaced in orientationfrom both of the rotatable parts 37 and 38; but optionally, the sheetmaterial of rotatable part 39 may be substantially oriented in a radialmanner comparable or radially identical to rotatable part 37, as is thecase in the showing of FIG. 4. (If desired, the axiallyoriented ends ofthe rotatable parts may be connected together by webs of material so asto give a screw effect or appearance to the entire rotating assembly;but this is not preferred and is merely an expedient for giving a joinedappearance to the parts.) A patterned area of reflex-reflecting material40, 41, and 42, illustratively shaped in the form of an arrow, is fixedto one side of each of the sheet materials comprising the rotatableparts 37, 38 and 39. Arrow 40 is on the reverse side of part 37 as shownin FIG. 4; and arrows 41 and 42 are shown on the side of sheet parts 38and 39 which one views when looking at FIG. 4. The arrows are alldisplaced in axial relationship from one another and preferably extendover the axis area of rotation. The opposing surface or opposite surface(not carrying an arrow) of each rotatable part is preferably entirelyfree of reflex-reflecting material in the embodiment illustrated in FIG.4. Each base sheet material part 37, 38, and 39 suitably is contoured topromote rotation as effected by wind acting thereupon. The effect of thearrangement in FIG. 4, when viewed under reflex-reflecting conditions,is that of providing the viewer with the impression of an arrow jumpingalong a line and then returning to its point of beginning and againjumping along a line. Thus the impression of a repetitive series ofarrows is gained. The arrangement (or alternate orientation of arrows orother directional shapes) is especially useful as a roadside signalerting drivers on the highway to the presence of a curve ahead or thelike. It also is useful to alert drivers to change lanes where a lane isblocked further ahead. In principle, it is even useful as an alternatearrangement (optionally with the arrow pattern replaced by a differentshape) for safety warning devices for bicycle riders.

The device of FIG. comprises a perimeter frame I member 43 of closedloop character. The closed loop Patterned areas of reflex-reflecting andnon-reflexreflecting material are on opposite sides of each base sheet50 and 51. The rotatable part identified as base sheet material 50 isequipped on one side with a strip pattern 48 of triangular shape inreflex-reflecting material, with a triangular center portion of thetriangular shape of reflex-reflecting material beingnon-reflexreflecting. All triangular shaped border areas ofreflexrcflecting material, as illustrated in FIG. 5, are characterizedby having a center triangular area of non-reflexreflecting material. Thetriangular reflex-reflecting pattern identified by numeral 49 is on thereverse side of the base sheet 50; and to be observed is that the bordertriangular reflex-reflecting pattern 49 is the mirror reciprocal orinversion of the reflex-reflecting pattern 48 on the face side of basesheet 50 as viewed in FIG. 5. Thus the patterns are relatively displacedin axial relationship and at least 50% of the area coverage of eachreflex-reflecting pattern on opposite sides is in a location relative tothe axis which does not coincide as viewed during rotation. In acomparable manner, the secondary base sheet material 51 in FIG. 5 isequipped with a border triangular pattern 46 of reflex-reflectingmaterial 46 on one side; and the reverse side of that base sheet 51 isequipped with a comparable border triangular pattern ofreflex-reflecting material 47. Again the patterns on opposite sides ofthe base sheet 51 are suitably substantially identical in overall shape;but the pattern on one side is inverted and therefore of different axialorientation from the pattern on the other. All areas of these basesheets 50 and 51, apart from the triangular strip patterns ofreflex-reflecting material, are non-reflex-reflecting and non-specularreflecting. lllustratively, the center island triangles on both sides ofeach base sheet 50 and 51 may be and preferably are covered withfluorescent material such as a fluorescent paint. If desired, all of theareas of the base sheets 50 and 51, apart from the reflex-reflectingareas, may be coated with fluorescent material. But preferably, theareas of base sheets 50 and 51 external to the border triangulation ofreflex-reflecting material are transparent. Upon rotation of the basesheet 50 and the secondary base sheet 51, about the axis under theinfluence of wind striking the base sheets and 51, the viewer underreflex-reflecting conditions gains the impression of shifting flashpatterns exhibiting alternate or inverted mirror image characteristics;and during daytime or dawn or dusk conditions, the alerting benefit ofjumping fluorescent light is exhibited by the rotating device. Thismakes the pattern arrangements especially useful on farm vehicles andother slow vehicles as a safety warning member having greaterattentiongetting qualities than a stationary marker on the vehicles. Therotating-arrangement is attention-getting even as the vehicle approachesa highway from a side road.

The device in FIG. 6 comprises a tripod frame, with three legs 52 hingedto an apex plate 53. Hinge 54, espe'cially when apex S3 and legs 52 areformed out of organic plastic, may consist of a fold of plasticmaterial. Alternately, metal hinges or other suitable hinging means maybe employed. Axis means 55, illustratively a simple string or strand orflexible wire with a swivel connector 58 interposed along the lengththereof, depends downwardly from apex 53. The lower end of the axisstrand 55 likewise is swivelly mounted, as at 56. Element 56 is suitablyheld in place by flexible links 57 extending substantially horizontallyfrom it to tripod legs 52. Links 57 brace or limit the spread of thelegs. Contoured from-retaining base sheet material 59 on axis 55 isactuatable into rotation by wind acting thereupon. A border striptriangular pattern of reflexreflecting material 60 onnon-reflex-reflecting background is carried on one side of base sheet59', and a comparable reflex-reflecting pattern 61 is carried on theother side, optionally with fluorescent material within the triangles,as aforenoted. Pattern 61 is shown substantially axially displaced fromthe pattern 60. Viewed under reflex-reflecting conditions, the alternateflashing effect of the patterns occurs at two distinctly differentlevels.

In FIG. 7, a safety warning device comparable to that illustrated inFIG. 1 is shown, with the exception that the frame structure for thedevice consists of a series of ring elements 62, 63 and 64. Ringelements 62 and 63 may be looked upon as disposed at right angles toeach other and oriented analogously to great circles of longitude (byanalogy to a globe). Ring element 64 is oriented at a locationcomparable to an equator line intersecting with the ring element 62 and63. Stub shafts 65 and 66 are suitably mounted inbearing surfaces at thepole intersections of ring elements 62 and 63. Rotatable base sheetmaterial 67 of contoured design (comparable in contour to thatillustrated in FIGS. 1 and 2 for the base sheet material shown therein)is equipped with patterned areas 68 and 69 of reflexreflecting materialon opposite sides thereof, with the patterns substantially displacedfrom each other so that no portions overlap as the device is viewedunder reflex-reflecting conditions. Other areas of the primary rotatablepart 67 are non-reflex-reflecting.

In FIG. 8 (which is a cross section through a formretaining body), threediscrete surface viewable areas 70, 71, and 72, are connected togetherin angular relationship to each other. These areas completely surroundand are spaced outwardly from the predetermined axis of rotationidentified by shaft 73. Fin-like projections 74 extend outwardly,suitably in curved contour, from the mass of the body defined by areas70, 71 and 72. They provide the means for wind actuation of the rotationof the composite body. Surface viewable areas 70, 71 and 72 preferablycontain or comprise at least substantial portions which aresubstantially parallel with the axis of rotation 73 for the body.Patterned areas of reflex-reflecting material, such as, for example, astar body of reflexreflecting material, are suitably positioned on eachviewable area 70, 71 and 72 at axially displaced locations, withoutradial overlap of the reflex-reflecting material on any side withrespect to the others as the structure is rotated and viewed underreflex-reflecting conditions. In any event, at least 50% of the areacoverage of reflex-reflection on any one side or portion of the surfaceviewable areas should be in locations not coinciding (to a viewer of therotating device under reflex-reflecting conditions) with the patternedarea of reflex-reflection at other radially displaced surface viewableareas. Illustratively, a discrete reflex-reflecting pattern on onesurface viewable side of the body may be located as at numeral 75, andanother as at numeral 76. The reflex-reflecting material at numeral 76is shown in cross section to illustrate the face that only part of thereflex-reflecting material at that location is viewed in thecross-section through the body. No reflex-reflecting material is shownon the surface viewable area identified at numeral 72 inasmuch as,hypothetically, the cross section for the body illustrated in FIG. 8 istaken at an intermediate plane or section along its length below thelocation for the pattern on side 72.

ln concept, surface viewable areas completely surrounding and spacedoutwardly from an axis of rotation may comprise or form a cylinder, oreven a shape suggestive of a globe or a cone; but usually, the shapewill be formed of discrete surface viewable areas or planes (orcurvi-planar surfaces) connected together in angular relationship aboutthe axis.

FIG. 9 constitutes an illustration of a curviplanar or contoured basesheet material 77 serving as a primary (or secondary) rotatable part fordevices according to the invention, but with the axis 78 for rotation ofthe sheet material displaced laterally from the body of the sheetmaterial. In short, the predetermined axis of rotation 78 lies in a linenot substantially coinciding with a line through the sheet material 77;but the sheet material is nevertheless so aligned with the axis thatsubstantially all portions of the sheet material, even though it issuitably contoured, extend substantially parallel with the axis 78 ofrotation. Sheet material 77 is suitably mounted for rotation about axis78 through, or by means of, a bracket member 79. While not preferred,this Figure illustrates that the structural relationship between arotating body or base sheet material (such as sheet material 77) and theaxis of rotation for it (such as axis 78) need not be such that therotation of the body or sheet material 77 is a perfectly balanceddisposition of the body or sheet material for rotation about an axis.

The base physical materials useful for fabricating devices of theinvention may vary widely, with metal and organic plastic being mostprefered from the practical standpoint of ease and economy in forming(by molding or pressing) a variety of rotatable sheet or body shapes andframe structures. The most essential feature, in terms ofreflex-reflection, is that of forming the pattern arrangements accordingto the teachings herein so as to gain the aforediscussed uniqueflickering performance under practical use conditions, even atrelatively high velocity of rotation.

That which is claimed is:

1. An eye-catching attention-getting safety device comprising at leastone primary rotatable part, an axis means establishing a predeterminedaxis about which rotation of said primary rotatable part is adapted totake place, and holding means for said axis means to pemrit saidrotation, said primary rotatable part comprising a form-retaining basesheet material aligned with substantially all portions thereof extendingsubstantially parallel with said predetermined axis, said sheet materialbeing contoured at least in portions outwardly from saidaxis, andpatterned areas of reflexreflecting material and ofnon-reflex-reflecting material on opposite sides of said sheet material,the patterned area of reflex-reflecting material on one side of saidsheet material being relatively displaced in axial relationship from thepatterned area of reflex-reflecting material on the other side thereof,at least 50 percent of the area coverage of each said reflex-reflectingpattern on opposite sides of said sheet material being in locationsrelative to said axis means which do not coincide as viewed duringrotation of said rotatable part, the patterned areas ofnon-reflex-reflecting material on opposite sides of said sheet materialalso being relatively displaced in axial relationship to each other,whereby substantially all practical rotation speeds for said primaryrotatable part about said predetermined axis provide a viewer underreflex-reflecting conditions with the impression of shifting flashpatterns of light return suggestive of the patterns of said areas ofreflexreflecting material.

2. The safety device of claim 1 wherein the reflexreflecting pattern onone side of said base sheet material is substantially identical inoverall shape to the reflex-reflecting pattern on the other side of saidsheet material. v

3. The safety device of claim 1 wherein said reflexreflecting pattern onsaid one side is of a shape which provides a recognizably differentpattern when ivnerted.

4. The safety device of claim 3 wherein said reflexreflecting patternson opposite sides of said sheet material are substantially identical inoverall shape but are inverted with respect to each other.

5. The safety device of claim 4 wherein at least a portion of saidpatterned areas of non-reflex-reflecting material on opposite sides ofsaid base sheet material comprises fluorescent material.

6. The safety device of claim 1 wherein substantially all of thepatterned areas of non-reflex-reflecting material on opposite sides ofthe base sheet material consists of fluorescent material.

7. The safety device of claim 1 wherein said reflexreflecting patternson opposite sides of said base sheet material contain no portion whichoverlaps as veiwed during rotation of said primary rotatable part.

8. The safety device of claim 1 wherein said predetermined axis extendsalong a line substantially coinciding with a line in the plane of saidbase sheet material.

9. The safety device of claim 8 wherein said reflexreflecting patternson opposite sides of said base sheet material extend across the axisarea of said sheet material.

10. The safety device of claim 1 wherein said axis means extends inopposite directions from said base sheet material and said holding meanscomprises a frame member having means cooperatively associated with eachend of said axis means to permit windactuated rotation of said primaryrotatable part.

11. The safety device of claim 10 wherein said frame member comprises atripod and said axis means depends downwardly from the apex of saidtripod.

12. The safety device of claim 1 additionally comprising a secondaryrotatable part mounted for rotation about said predetermined axis, saidsecondary rotatable part being axially and radially displaced from saidprimary rotatable part and comprising a secondary form-retaining sheetmaterial aligned with substantially all portions thereof extendingsubstantially parallel with said predetermined axis.

13. The safety device of claim 1 wherein at least a portion of saidpatterned areas of non-reflex-reflecting material onopposite sides ofsaid base sheet material comprises fluorescent material.

14. The safety device of claim 13 wherein said reflexreflecting patternson opposite sides contain no portion which overlaps in an axialdirection during rotation of said primary rotatable part.

15. The safety device of claim 1 wherein said primary rotatable part isactuatable into rotation by wind acting thereupon, wherein saidreflex-reflecting pattern on each side of said sheet material is of ashape which provides a recognizably different pattern when inverted, andwherein said reflex-reflecting patterns on opposite sides contain noportion which overlaps in an axial direction during rotation of saidprimary rotatable part.

16. An eye-catching attention-getting safety device comprising at leastone primary rotatable part, an axis means establishing a predeterminedaxis about which rotation of said primary rotatable part is adapted totake place, and holding means for said axis means to permit saidrotation, said primary rotatable part comprising a form-retaining bodyhaving surface viewable areas completely surrounding and spacedoutwardly from said predetermined axis, and at least two patterned areasof reflex-reflecting material on background areas ofnon-reflex-reflecting material, said reflex-reflecting patterns beingrelatively displaced from each other in both axial relationship andradial relationship on said surface viewable areas, with at least one ofsaid patterns of reflex-reflecting material not extending in acircumferential direction any more than degrees about said predeterminedaxis, whereby substantially all practical rotation speeds for said bodyabout said predetermined axis provide a viewer under reflex-reflectingconditions with the impression of shifting flash patterns of lightsuggestive of the patterns of said areas of reflex-reflecting material.

17. The safety device of claim 16 wherein the portions of said surfaceviewable areas carrying said reflexreflecting material are disposedsubstantially parallel to said predetermined axis.

18. The safety device of claim 16 wherein said surface viewable areas ofsaid body are disposed to form at least three discrete surface viewablearea portions connected in angular relationship to each other.

19. The safety device of claim 16 additionally comprising meansfacilitating wind actuation of the rotation thereof.

20. An eye-catching attention-getting safety device comprising at leastone primary rotatable part, an axis means establishing a predeterminedaxis about which rotation of said primary rotatable part is adapted totake place, holding means for said axis means to permit said rotation,and at least one secondary rotatable part mounted for rotation aboutsaid predetermined axis, said secondary rotatable part being axiallydisplaced from said primary rotatable part, said primary rotatable partand said secondary rotatable part each consisting essentially of aform-retaining base sheet material aligned with substantially allportions of the sheet material extending substantially parallel withsaid predetermined axis, said sheet material of said primary rotatablepart being radially displaced in orientation from said sheet material ofsaid secondary rotatable part, and a patterned area of reflex-reflectingmaterial on one side of each said sheet material, the other side of eachsaid sheet material containing no area of reflexreflection axiallyoverlapping said patterned area of said one side, whereby substantiallyall practical rotation speeds for said rotatable parts about saidpredetermined axis provide a viewer under reflex-reflecting conditionswith the impression of shifting flash patterns of light returnsuggestive of the patterns of saidareas of reflex-reflecting material.

21. The safety device of claim 20 wherein said patterned area ofreflex-reflecting material on said one side of said sheet material ofsaid secondary rotatable 22. The safety device of claim 20 additionallycompart is identical to said patterned area of reflexprising meansfacilitating wind actuation of the rotation reflecting material on saidone side of said sheet matethereof.

rial of said primary rotatable part.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,759 Dated September 973 Inventor(s) Donald J. Douglas It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column ll, line 65, "face should read feet Column 12, line 51, "pemritshould read permit Column 13, lines 16-17 (claim 3) "ivner'ted shouldread inverted Signed and sealed this 21st day of May 197M.

(SEAL) Atte e EDI IARD M .FLETCHER JR C i-IARSHALL DANN Atte stingOfficer Commissioner of Patents ORM PO-l 050 (10-69) UscoMM-oc soon-P69V ".5. GOVERNMENT PRINTING OFFICE 2 I969 0-366'33L

1. An eye-catching attention-getting safety device comprising at least one primary rotatable part, an axis means establishing a predetermined axis about which rotation of said primary rotatable part is adapted to take place, and holding means for said axis means to pemrit said rotation, said primary rotatable part comprising a form-retaining base sheet material aligned with substantially all portions thereof extending substantially parallel with said predetermined axis, said sheet material being contoured at least in portions outwardly from said axis, and patterned areas of reflex-reflecting material and of non-reflexreflecting material on opposite sides of said sheet material, the patterned area of reflex-reflecting material on one side of said sheet material being relatively displaced in axial relationship from the patterned area of reflex-reflecting material on the other side thereof, at least 50 percent of the area coverage of each said reflex-reflecting pattern on opposite sides of said sheet material being in locations relative to said axis means which do not coincide as viewed during rotation of said rotatable part, the patterned areas of non-reflex-reflecting material on opposite sides of said sheet material also being relatively displaced in axial relationship to each other, whereby substantially all practical rotation speeds for said primary rotatable part about said predetermined axis provide a viewer under reflex-reflecting conditions with the impression of shifting flash patterns of light return suggestive of the patterns of said areas of reflex-reflecting material.
 2. The safety device of claim 1 wherein the reflex-reflecting pattern on one side of said base sheet material is substantially identical in overall shape to the reflex-reflecting pattern on the other side of said sheet material.
 3. The safety device of claim 1 wherein said reflex-reflecting pattern on said one side is of a shape which provides a recognizably different pattern when ivnerted.
 4. The safety device of claim 3 wherein said reflex-reflecting patterns on opposite sides of said sheet material are substantially identical in overall shape but are inverted with respect to each other.
 5. The safety device of claim 4 wherein at least a portion of said patterned areas of non-reflex-reflecting material on opposite sides of said base sheet material comprises fluorescent material.
 6. The safety device of claim 1 wherein substantially all of the patterned areas of non-reflex-reflecting material on opposite sides of the base sheet material consists of fluorescent material.
 7. The safety device of claim 1 wherein said reflex-reflecting patterns on opposite sides of said base sheet material contain no portion which overlaps as veiwed during rotation of said primary rotatable part.
 8. The safety device of claim 1 wherein said predetermined axis extends along a line substantially coinciding with a line in the plane of said base sheet material.
 9. The safety device of claim 8 wherein said reflex-reflecting patterns on opposite sides of said base sheet material extend across the axis area of said sheet material.
 10. The safety device of claim 1 wherein said axis means extends in opposite directions from said base sheet material and said holding means comprises a frame member having means cooperatively associated with each end of said axis means to permit wind-actuated rotation of said primary rotatable part.
 11. The safety device of claim 10 wherein said frame member comprises a tripod and said axis means depends downwardly from the apex of said tripod.
 12. THe safety device of claim 1 additionally comprising a secondary rotatable part mounted for rotation about said predetermined axis, said secondary rotatable part being axially and radially displaced from said primary rotatable part and comprising a secondary form-retaining sheet material aligned with substantially all portions thereof extending substantially parallel with said predetermined axis.
 13. The safety device of claim 1 wherein at least a portion of said patterned areas of non-reflex-reflecting material on opposite sides of said base sheet material comprises fluorescent material.
 14. The safety device of claim 13 wherein said reflex-reflecting patterns on opposite sides contain no portion which overlaps in an axial direction during rotation of said primary rotatable part.
 15. The safety device of claim 1 wherein said primary rotatable part is actuatable into rotation by wind acting thereupon, wherein said reflex-reflecting pattern on each side of said sheet material is of a shape which provides a recognizably different pattern when inverted, and wherein said reflex-reflecting patterns on opposite sides contain no portion which overlaps in an axial direction during rotation of said primary rotatable part.
 16. An eye-catching attention-getting safety device comprising at least one primary rotatable part, an axis means establishing a predetermined axis about which rotation of said primary rotatable part is adapted to take place, and holding means for said axis means to permit said rotation, said primary rotatable part comprising a form-retaining body having surface viewable areas completely surrounding and spaced outwardly from said predetermined axis, and at least two patterned areas of reflex-reflecting material on background areas of non-reflex-reflecting material, said reflex-reflecting patterns being relatively displaced from each other in both axial relationship and radial relationship on said surface viewable areas, with at least one of said patterns of reflex-reflecting material not extending in a circumferential direction any more than 180 degrees about said predetermined axis, whereby substantially all practical rotation speeds for said body about said predetermined axis provide a viewer under reflex-reflecting conditions with the impression of shifting flash patterns of light suggestive of the patterns of said areas of reflex-reflecting material.
 17. The safety device of claim 16 wherein the portions of said surface viewable areas carrying said reflex-reflecting material are disposed substantially parallel to said predetermined axis.
 18. The safety device of claim 16 wherein said surface viewable areas of said body are disposed to form at least three discrete surface viewable area portions connected in angular relationship to each other.
 19. The safety device of claim 16 additionally comprising means facilitating wind actuation of the rotation thereof.
 20. An eye-catching attention-getting safety device comprising at least one primary rotatable part, an axis means establishing a predetermined axis about which rotation of said primary rotatable part is adapted to take place, holding means for said axis means to permit said rotation, and at least one secondary rotatable part mounted for rotation about said predetermined axis, said secondary rotatable part being axially displaced from said primary rotatable part, said primary rotatable part and said secondary rotatable part each consisting essentially of a form-retaining base sheet material aligned with substantially all portions of the sheet material extending substantially parallel with said predetermined axis, said sheet material of said primary rotatable part being radially displaced in orientation from said sheet material of said secondary rotatable part, and a patterned area of reflex-reflecting material on one side of each said sheet material, the other side of each said sheet material containing no area of reflex-reflection axially overlapping said patterned area of said one side, whereby substantially all practical rotation speeds for said rotatable parts about said predetermined axis provide a viewer under reflex-reflecting conditions with the impression of shifting flash patterns of light return suggestive of the patterns of said areas of reflex-reflecting material.
 21. The safety device of claim 20 wherein said patterned area of reflex-reflecting material on said one side of said sheet material of said secondary rotatable part is identical to said patterned area of reflex-reflecting material on said one side of said sheet material of said primary rotatable part.
 22. The safety device of claim 20 additionally comprising means facilitating wind actuation of the rotation thereof. 